Portion of a pillow



FIG. 1 is a first perspective view thereof;

FIG. 2 is a top view thereof;

FIG. 3 is a first side view thereof;

FIG. 4 is a first end view thereof

FIG. 5 is a second side view thereof;

FIG. 6 is a second end view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in the drawings are for environmental purposes only and form no part of the claimed design. 

The ornamental design for a portion of a pillow, as shown and described. 